This page is for pediatric patients. For adult patients, see: asthma
Background
Comparison of normal airway (B) to airway during asthma symptoms (C).
Features of remodeling in asthma.
- An estimated 6 million children in the US have asthma
- In 2007, asthma lead to >700,000 ED visits
- Asthma is part of the atopy triad (asthma, allergies, eczema)
- A history of eczema or allergies maybe helpful in making a new diagnosis of asthma
- Wheezing in an infant is more often bronchiolitis than asthma
- Viral URI associated with copious rhinorrhea, allergen exposure, and respiratory irritants (i.e. smoke) are common precipitants for pediatric asthma exacerbations
Clinical Features
- Wheezing
- Cough
- Accessory muscle use
- Dyspnea
- Prolonged expiration
- Severity of retractions occurs in caudal to cephalad direction
- Scalene muscle contractions more severe than subcostal and intercostal retractions
- Sign of impending ventilatory failure
- Paradoxical respiration
- Chest deflation and abdominal protrusion during inspiration
- Altered mental status
- "Silent chest"
Differential Diagnosis
Pediatric Wheezing
- Upper Airway diseases
- Large Airway Obstruction
- Small Airway Obstruction
- Other causes
Evaluation
CXR with hyperinflated lungs consistent with broncoconstriction.
- Clinical diagnosis
- Can consider a blood gas if there are fears that the patient is getting tired (sleepy baby vs elevated CO2?)
- A CO2 >45 is abnormal in a patient hyperventilating and warrants close monitoring
Consider CXR
- 1st wheezing episode
- Asymmetric lung auscultation findings, after treatment with albuterol
- Poor response to medications/treatment, if history and exam are not consistent with bronchiolitis
- Worsening symptoms
- Fever not explained by apparent viral illness
Clinical Scores
- Diagnosis and treatment can be guided by clinical scores
- Modified Pulmonary Index Score (MPIS - Utilized at CCMC)
- Pediatric Asthma Score (PAS)
- Pulmonary Score (PS)
- Pediatric Respiratory Assessment Measure (PRAM)
Modified Pulmonary Index Score (MPIS)
Age <3 Years
|
Points |
SpO2 |
Acces Musc Use |
I:E |
Wheeze |
HR |
RR
|
0 |
>95% |
None |
2:1 |
None; Good Aeration |
≤120 |
≤30
|
1 |
93-95% |
Mild |
1:1 |
End Exp |
121-140 |
31-45
|
2 |
90-92% |
Moderate |
1:2 |
Insp/Exp; Good Aeration |
141-160 |
46-60
|
3 |
<90% |
Severe |
1:3 |
Insp/Exp; Poor Aeration |
>160 |
>60
|
Age 3-6 Years
|
Points |
SpO2 |
Acces Musc Use |
I:E |
Wheeze |
HR |
RR
|
0 |
>95% |
None |
2:1 |
None; Good Aeration |
≤100 |
≤30
|
1 |
93-95% |
Mild |
1:1 |
End Exp |
101-120 |
31-45
|
2 |
90-92% |
Moderate |
1:2 |
Insp/Exp; Good Aeration |
121-140 |
46-60
|
3 |
<90% |
Severe |
1:3 |
Insp/Exp; Poor Aeration |
>140 |
>60
|
Age ≥6 Years
|
Points |
SpO2 |
Acces Musc Use |
I:E |
Wheeze |
HR |
RR
|
0 |
>95% |
None |
2:1 |
None; Good Aeration |
≤100 |
≤20
|
1 |
93-95% |
Mild |
1:1 |
End Exp |
101-120 |
21-35
|
2 |
90-92% |
Moderate |
1:2 |
Insp/Exp; Good Aeration |
121-140 |
36-50
|
3 |
<90% |
Severe |
1:3 |
Insp/Exp; Poor Aeration |
>140 |
>50
|
- MPIS <7 - Mild exacerbation
- MPIS 7-10 - Moderate exacerbation
- MPIS ≥10 - Severe exacerbation
Management
Favor continuous nebulization to decrease the chance of admission when compared to intermittent dosing[1]
- Nebulizer
- Intermittent: 2.5-5mg q20min, three doses are traditionally given back to back, then repeat as needed.
- Continuous: 0.5mg/kg/hr (max 15mg/hr)[2]
- MDI
- 4-8 puffs q20min given in first hour, then q1-4hr as needed
- 0.25-0.5mg q20min, given with the first three doses of albuterol, it is shown to reduce admission.
Should be given in the first hour with effects to reduce admission[3]
- Dexamethasone
- 0.6 mg/kg PO or IV (max 16 mg); consider 2nd dose 24-36hrs later.[4][5][6]
- PO and IV have equal efficacy. Giving the IV form by mouth is typically better tolerated by young children (same dosing)
- Both 1 and 2 dose regimens as effective as prednisone or prednisolone in children [7][8]
- Prednisone
- 1-2mg/kg/day (60mg max) in one or two divided doses for 3-5 days
- Methylprednisolone
- 1mg/kg IV q 4–6hr
- Only use IV if cannot tolerate PO since equal effectiveness between dosing routes[9]
- Dose: 50mg/kg IV, max 2-4 g over 20 mins with close blood pressure monitoring
- Smooth muscle relaxant
- Duration of action approximately 20 min
- In patients with moderate to severe asthma there is a decreased rate of admission with an NNT of 2[3]
Beta-agonist
- Epinephrine
- 1:1000 0.01mg/kg (max 0.3mg) IM, repeat as needed
- Terbutaline
- Given SQ, usual dose 0.01mg/kg up to 0.3mg.
- Longer-acting beta2-agonist promoting bronchodilation
Assisted Ventilation
- Non-invasive ventilation
- Consider as alternative to intubation
- Alleviates muscle fatigue which leads to larger tidal volumes
- Maximize inspiratory support
- Delta pressure 10
- PEEP >4
- May benefit from ketamine or dexmedetomidine to mildly sedate and allow the interface
- Push pull (bolus) fluids prior to intubation to maximize the patient's preload and ideally decrease the chance of the patient arresting
- Consider induction with ketamine
- Provides bronchodilation and sedation however it does promote secretions
- Ketamine is the preferred induction agent for intubation in an asthmatic.
- Dosing 1-2 mg/kg
- Ventilation of asthmatic patients requires deep sedation
- Ventilation settings
- Assist-control ventilation
- Resp rate
- Start slow to avoid air-trapping and allow for longer expiration time
- Consider I:E ratio of 1:2 or 1:3
- Plateau pressure ideally <30
- May require "permissive hypoventilation" and permissive hypercarbia and acidosis
- Low peak pressure/avoidance of breath stacking more important than correcting CO2 [10]
- Tidal volume 6-8cc/kg ideal wt
- PEEP >4
- Flow rate 80-100L/min
- Keep FiO2 minimum to achieve SpO2 > 90%
- Use bronchodilators even when intubated
- Many patients require a continuous paralytic infusion for the first 24+ hrs of intubation
Outpatient Treatment
Severity
|
Day Sx
|
Night Sx
|
Treatment (WHO 2008 Formulary)[11]
|
Mild intermittent, > 80% peak flow |
< 2/wk |
< 2/mo |
|
Mild persistent, > 80% peak flow |
>2/wk |
>2/mo |
|
Moderate persistent, 60-80% peak flow |
Daily with exacerbations weekly |
> 1/wk |
|
Severe persistent, < 60% peak flow |
Continuous daily |
Frequent |
|
Disposition
- Discharge
- Often, patients will still have mild wheezing, but should have complete resolution of tachypnea, hypoxia, and improved work of breathing
- A short course of glucocorticoids decreases chance of relapse [12])
- Patient should generally continue albuterol at home q6hrs for at least the first 24hrs after discharge
- A spacer should be prescribed to be used with the MDI to improve medication delivery to the lungs
- Admit
- If symptoms do not significantly improve or for severe exacerbations
- Peak flow measurements maybe helpful when deciding disposition
- Predicted = (30 x age (yrs)) + 30
- PEF >70% predicted → high likelihood of successful discharge
- PEF <40% predicted → should be admitted
See Also
External Links
References
- ↑ Camargo CA et al. Continuous versus intermittent beta- agonists for acute asthma. Cochrane Database Syst Rev. 2003;(4):CD001115. PMID: 14583926.
- ↑ National Asthma Education and Prevention Program (NAEPP), “Expert Panel Report 3 (EPR-3): Guidelines for the Diagnosis and Management of Asthma,” Clinical Practice Guidelines, National Institutes of Health, National Heart, Lung, and Blood Institute, NIH Publication No. 08-4051, prepublication 2007; available at http://www.nhlbi.nih.gov/guidelines/asthma/asthgdln.htm.
- ↑ 3.0 3.1 Rowe BH et al. Magnesium sulfate for treating exac- erbations of acute asthma in the emergency depart- ment. Cochrane Database Syst Rev. 2000;(2):CD001490. PMID: 10796650.
- ↑ Cross KP, et al. Single-dose dexamethasone for mild-to-moderate asthma exacerbations. Can Fam Physician. 2011 Oct; 57(10): 1134–1136.
- ↑ Shenoi RP, Timm N; Committee on Drugs; Committee on Pediatric Emergency Medicine. Drugs used to treat pediatric emergencies. Pediatrics. 2020;145(1):e20193450. [PubMed 31871244]
- ↑ Dexamethasone versus prednisone for children receiving asthma treatment in the paediatric inpatient population: protocol for a feasibility randomised controlled trial. BMJ Open. http://dx.doi.org/10.1136/bmjopen-2018-025630
- ↑ Keeney, et al. Dexamethasone for Acute Asthma Exacerbations in Children: A Meta-analysis. Pediatrics. 2013-2273
- ↑ Cronin et al. "A Randomized Trial of Single-Dose Oral Dexamethasone Versus Multidose Prednisolone for Acute Exacerbations of Asthma in Children Who Attend the Emergency Department." Annals of EM. May 2016. 67(5):593-601
- ↑ Rowe BH, Keller JL, Oxman AD. Effectiveness of steroid therapy in acute exacerbations of asthma: a meta-analysis. Am J Emerg Med. Jul 1992;10(4):301-10
- ↑ Darioli, et al. Mechanical Controlled hypoventilation in status asthmaticus. Am Rev Respir Dis. 1984; 129 (3) 385-7
- ↑ Stuart MC et al. WHO Model Formulary 2008. http://www.who.int/selection_medicines/list/WMF2008.pdf.
- ↑ Chapman K. Effect of a short course of prednisone in the prevention of early relapse after the emergency room treatment of acute asthma. NEJM. 1991;324(12):788